<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no" />
    <title>Document</title>
  
  </head>
  <body>
    <div id="app">
        <button @click="doubleNum = 500">直接给计算属性赋值</button>
        {{num}}
        <br>
        {{doubleNum}}
    </div>
    <script src="./vue.global.js"></script>
    <script>
      const { createApp } = Vue;
      const app = createApp({
        data() {
          return {
            num: 50
          };
        },
        
        computed: {
          doubleNum: {
            get(){
              return this.num * 2
            },
            set(val){
              console.log('计算属性赋值了', val);
              this.num = val / 2;
            }
          }
        },
       
      });
      app.mount("#app");
    </script>
  </body>
</html>
